Decoding device, decoding method, coding device, and coding method

Abstract

The present disclosure relates to a decoding device, a decoding method, a coding device, and a coding method capable of improving coding efficiency of an image layered for each gamut. A gamut conversion unit converts a gamut of a decoded image of a base layer into a gamut of an enhancement layer. An adaptive offset unit performs a filter process on a predetermined band of the decoded image of the base layer subjected to the gamut conversion. An addition unit decodes a coded image of the enhancement layer using the decoded image of the base layer subjected to the filter process to generate a decoded image of the enhancement layer. The present disclosure can be applied to, for example, the decoding device.

1 . A decoding device comprising:
 a reception unit that receives a coded image of a first layer in an image layered for each gamut;   a gamut conversion unit that converts a gamut of a decoded image of a second layer into a gamut of the first layer;   a filter processing unit that performs a filter process on a predetermined band of the decoded image of the second layer converted by the gamut conversion unit; and   a decoding unit that decodes the coded image of the first layer received by the reception unit using the decoded image of the second layer subjected to the filter process by the filter processing unit to generate a decoded image of the first layer.   
     
     
         2 . The decoding device according to  claim 1 ,
 wherein the filter processing unit performs the filter process on the decoded image of the first layer decoded by the decoding unit, and   wherein the decoding unit decodes the coded image of the first layer using the decoded image of the first layer and the decoded image of the second layer subjected to the filter process by the filter processing.   
     
     
         3 . The decoding device according to  claim 2 , wherein the filter processing unit performs a sample adaptive offset (SAO) process on the predetermined band of the decoded image of the second layer and the decoded image of the first layer. 
     
     
         4 . The decoding device according to  claim 3 , wherein the filter processing unit performs a band offset process on the predetermined band of the decoded image of the second layer. 
     
     
         5 . The decoding device according to  claim 4 , wherein the filter processing unit performs the band offset process on a low-luminance band of the decoded image of the second layer. 
     
     
         6 . The decoding device according to  claim 4 , wherein the filter processing unit performs the band offset process on a high-luminance band of the decoded image of the second layer. 
     
     
         7 . The decoding device according to  claim 1 ,
 wherein the reception unit receives a parameter of the filter process, and   wherein the filter processing unit performs the filter process on the predetermined band of the decoded image of the second layer using the parameter received by the reception unit.   
     
     
         8 . The decoding device according to  claim 7 , wherein the reception unit receives the parameter in a largest coding unit (LCU). 
     
     
         9 . A decoding method in a decoding device, comprising:
 a reception step of receiving a coded image of a first layer in an image layered for each gamut;   a gamut conversion step of converting a gamut of a decoded image of a second layer into a gamut of the first layer;   a filter processing step of performing a filter process on a predetermined band of the decoded image of the second layer converted in a process of the gamut conversion step; and   a decoding step of decoding the coded image of the first layer received in a process of the reception step using the decoded image of the second layer subjected to the filter process in a process of the filter processing step to generate a decoded image of the first layer.   
     
     
         10 . A coding device comprising:
 a gamut conversion unit that converts a gamut of a decoded image of a second layer used for coding of an image of a first layer in an image layered for each gamut into a gamut of the first layer;   a filter processing unit that performs a filter process on a predetermined band of the decoded image of the second layer converted by the gamut conversion unit;   a coding unit that codes the image of the first layer using the decoded image of the second layer subjected to the filter process by the filter processing to generate a coded image of the first layer; and   a transmission unit that transmits the coded image of the first layer generated by the coding unit.   
     
     
         11 . The coding device according to  claim 10 , further comprising:
 a decoding unit that decodes the coded image of the first layer to generate a decoded image of the first layer,   wherein the filter processing performs the filter process on the decoded image of the first layer decoded by the decoding unit, and   wherein the coding unit codes the image of the first layer using the decoded image of the first layer and the decoded image of the second layer subjected to the filter process by the filter processing.   
     
     
         12 . The coding device according to  claim 11 , wherein the filter processing unit performs a sample adaptive offset (SAO) process on the predetermined band of the decoded image of the second layer and the decoded image of the first layer. 
     
     
         13 . The coding device according to  claim 12 , wherein the filter processing unit performs a band offset process on the predetermined band of the decoded image of the second layer. 
     
     
         14 . The coding device according to  claim 13 , wherein the filter processing unit performs the band offset process on a low-luminance band of the decoded image of the second layer. 
     
     
         15 . The coding device according to  claim 13 , wherein the filter processing unit performs the band offset process on a high-luminance band of the decoded image of the second layer. 
     
     
         16 . The coding device according to  claim 10 , further comprising:
 a calculation unit that calculates a parameter of the filter process,   wherein the filter processing unit performs the filter process on the predetermined band of the decoded image of the second layer using the parameter calculated by the calculation unit, and   wherein the transmission unit transmits the parameter.   
     
     
         17 . The coding device according to  claim 16 , wherein the calculation unit calculates the parameter in a largest coding unit (LCU). 
     
     
         18 . A coding method in a coding device, comprising:
 a gamut conversion step of converting a gamut of a decoded image of a second layer used for coding of an image of a first layer in an image layered for each gamut into a gamut of the first layer;   a filter processing step of performing a filter process on a predetermined band of the decoded image of the second layer converted in a process of the gamut conversion step;   a coding step of coding the image of the first layer using the decoded image of the second layer subjected to the filter process by the filter processing to generate a coded image of the first layer; and   a transmission step of transmitting the coded image of the first layer generated in a process of the coding step.